The Nature of Matter
Name: ______________________________
Section 2.1
Date: _________________ Period: ______
Lesson Objectives
Identify the three subatomic particles found in atoms.
Explain how all of the isotopes of an element are similar and how they are different.
Explain how compounds are different from their component elements.
Lesson Summary
Atoms - The atom is the basic unit of matter, made up of three subatomic particles.
Protons have a positive charge and neutrons carry no charge. Strong forces bind protons and neutrons together in the
nucleus.
An electron is a negatively charged particle that has only about 1/1840 the mass of a proton. Electrons constantly
move around the space surrounding the atom’s nucleus.
Because an atom has the same number of protons and electrons, if it is electrically neutral.
Elements and Isotopes - A chemical element is a pure substance that consists entirely of one type of atom.
Atoms of the same element that differ in the number of neutrons are called isotopes. Isotopes are identified by their
mass number, the total number of protons and neutrons in the nucleus. Because they have the same number of
electrons in each atom, all isotopes of an element have the same chemical properties.
Radioactive isotopes have unstable nuclei and break down at a constant rate.
Chemical Compounds - A chemical compound is a substance formed by the chemical combination of two or more
elements in definite proportions. The physical and chemical properties of a compound are usually very different from
those of the elements from which it is formed. Scientists use formulas to show the ratio of elements that make up a
compound.
Chemical Bonds - The atoms in compounds are held together by chemical bonds. Electrons that are available to form
bonds are called valence electrons.
An ionic bond forms when one or more electrons are transferred from one atom to another, forming ions. An atom
that loses electrons becomes positively charged. An atom that gains electrons becomes negatively charged.
A covalent bond forms when electrons are shared rather than transferred. The structure formed by atoms joined by
covalent bonds is called a molecule. The molecule is the smallest unit of most compounds.
When molecules are close together, a slight attraction can form between the oppositely charged portions of nearby
molecules. These intermolecular forces of attraction are called van der Waals forces.
Questions:
1. A chemical element is a pure substance that consists entirely of one type of
.
2. Atoms of the same element that differ in the number of neutrons they contain are called
3. An atom is made up of protons, neutrons, and
.
4. The nucleus, the center of the atom, is made up of __________________ and __________________.
5. The negatively charged particles in atoms are called __________________.
6. In a/an _____________________ bond, electrons are transferred between atoms.
1
7. What is a chemical compound?
8. What do the formulas for table salt, NaCl, and water, H2O, indicate about these compounds?
9. What is the difference between an ionic bond and a covalent bond?
10. Explain how an atom becomes an ion.
11. Explain the difference between a cation and an anion and give an example of each.
12. What are the similarities and differences between protons and neutrons?
13. What are the similarities and differences between protons and electrons?
14. What is the relationship between atoms and molecules?
15. Atoms are electrically
.
16. If atoms lose one electron, they become _______________ charged particles or __________________ and
will have a ____________________ charge. If they lose 1 electron, the charge will be ___________and if
they lose 2 electrons, the charge will be ___________.
17. If atoms gain electron(s), they will have a ____________________ charge. If they gain 1 electron, the
charge will be _________ and if they gain 2, the charge will be ______________.
2
COUNTING ATOMS
Name:
Period:
Biology
Date:
Directions: Determine how many atoms of each element are present in the following compounds.
FORMULA
2NaHCO3
1.
C2H4O2
2.
Mg(OH)2
3.
3H3PO4
4.
2H2SO4
5.
(NH4)3PO4
6.
4CaCO3
7.
3Ba(OH)2
8.
CH3CH2OH
9.
4Ca(ClO3)2
10.
Al2(SO4)3
11.
3(NH4)2SO4
# MOLECULES
# INDIVIDUAL ATOMS
# TOTAL ATOMS
2
Na: 2 x 1 = 2
H: 2 x 1 = 2
C: 2 x 1 = 2
O: 2 x 3 = 6
12
3
Water Molecule Kit
1) Put the water molecules together.
a. What is the formula for water?
b. Draw and label a molecule of water. Place a + symbol on each hydrogen and 2 – symbols on the
oxygen.
2) What will happen when two water molecules bump into each other?
a. Draw 2 additional molecules of water with the molecule you drew in 1b (there should be 3
molecules of water now).
b. What are the similarities and differences between magnets and water molecules?
3) Where are covalent bonds found in the model?
4) Where are hydrogen bonds found in the model?
5) What is the difference between intramolecular bonds and intermolecular forces? Think about what
INTRA vs. INTER means (interstate vs. intrastate, intersection, etc.).
6) Try to break the “bond” between the water molecules by pulling them apart. Compare this to the
relative strength of pulling a hydrogen atom off a water molecule.
a. What is the intermolecular that holds the two water molecules together?
b. What is the intramolecular bond that holds the hydrogen atoms and oxygen atom within a water
molecule?
7) Use the sodium chloride (NaCl) – blue and green atoms – to determine how it interacts with the water
molecules.
a. Will a water molecule interact with sodium chloride? Why?
b. What is the intramolecular bond that holds sodium and chloride ions together?
c. Are there hydrogen bonds formed between water and sodium chloride?
8) Take a look at ethane (teacher model).
a. What is the formula for ethane?
b. Do the ethane molecules “stick” together?
c. Do the ethane molecules “stick” to water?
d. Is a water molecule a polar covalent or a nonpolar covalent molecule?
e. Is ethane a polar covalent or a nonpolar covalent molecule?
f. Will ethane form a hydrogen bond with water?
4
PROPERTIES OF WATER
Biology
Name:
Date:
Period:
Read the following passage and answer the questions in the space provided.
An attractive force between particles of the same kind is known as cohesion. Cohesive forces
resulting from water’s hydrogen bonding are strong enough to cause water to act as if it has a
thin “skin” on its surface. This is why water appears to bulge from the sides of a glass filled to
the brim.
Adhesion is the attractive force between unlike substances. Together, adhesion and cohesion
enable water molecules to move upward through narrow tubes against the force of gravity. This
property of water is known as capillarity.
VOCABULARY REVIEW: Define the following terms.
1) polar compound
2) hydrogen bond
3) cohesion
4) adhesion
RECOGNIZING SIMILARITIES AND DIFFERENCES
5) How are cohesion and adhesion alike?
6) How are cohesion and adhesion different?
3-1 REVIEW
5
TRUE or FALSE: For Questions 7-10, write True or False on the line provided. If it is false correct the
underlined word.
_____________ 7.
Water is a polar molecule.
_____________ 8.
Hydrogen bonds are an example of adhesion.
_____________ 9.
Covalent bonds give water a high heat capacity.
_____________ 10.
A hydrogen bond is stronger than a covalent bond.
MULTIPLE CHOICE: Circle the letter of the word or phrase that best completes the statement.
11) The thin “skin” that appears to form on water’s surface occurs because of
a. cohesion.
b. adhesion.
c. capillarity.
d. both (a) and (b)
12) In a water molecule,
a. all of the atoms have a slight positive charge.
b. the oxygen atom has a slight negative charge and the hydrogen atoms have slight positive charge.
c. the oxygen atom has a slight positive charge and the hydrogen atoms have a slight negative charge.
d. all of the atoms have a slight negative charge.
13) When sodium chloride is dissolved in water, the sodium ions
a. are attracted to the oxygen atoms of water molecules.
b. are attracted to the hydrogen atoms of water molecules.
c. are attracted to each other.
d. do not dissociate from the sodium chloride.
14) Hydrogen bonds
a. form between hydrogen atoms in different molecules.
b. are strong bonds.
c. hold water molecules to one another.
d. hold the two hydrogen atoms together in a molecule of hydrogen gas, H2.
15) When a glass is filled to the brim with water, the water appears to bulge from the sides of the glass due to
a. capillarity.
b. thermal energy.
c. adhesion.
d. cohesion.
16) When liquid water is heated, most of the energy that the water initially absorbs is used to
a. raise the temperature of the water.
b. break the covalent bonds between the hydrogen and oxygen atoms in water.
c. make the water boil.
d. break the hydrogen bonds between the water molecules.
SHORT ANSWER: Answer the questions in the space provided.
17) Why is water a good solvent?
6
18) What kinds of substances besides water can be involved in hydrogen bonding?
19) What property of water allows it to stick to a dry surface, such as a wooden countertop?
20) How does water help cells keep an even temperature despite temperature changes in the environment?
21) Explain why water forms large, round drops as it falls from a faucet with a slow leak.
22) Water is often called the universal solvent because it dissolves most substances that are important to living
things. What does this suggest about the nature of those substances?
STRUCTURES AND FUNCTIONS
23) The diagram below represents a single water molecule. Draw THREE other water molecules near it, and use
dashed lines to indicate where HYDROGEN bonds would form between the molecule shown below and the
ones you drew.
7
CLASSIFICATION
Name: ________________________
Biology
Date: ___________ Period: ______
Solutions and Suspensions - Complete the table
Substance
Definition
Example(s)
Cinnamon sugar
Physical combination of two or more substances
Solute
Salt in saltwater
Solvent
Mixture of water and nondissolved substance
Blood
Solution
Match each of the following statements with one or more of the following forms of matter.
(E) Element
(C) Compound
(S) Solution
(M) Heterogeneous Mixture
______ 1.
Dirt
______ 14.
Baking soda (NaHCO3)
______ 2.
CH3OCH3
______ 15.
Mercury
______ 3.
Perfume
______ 16.
Tap water
______ 4.
Nitrogen gas (N2)
______ 17.
Distilled Water
______ 5.
Air (O2, N2, CO2, Ar)
______ 18.
14-carat gold ring
______ 6.
Jell-O
______ 19.
Diamond
______ 7.
Tin
______ 20.
Scoop of Beach Sand
______ 8.
CO2
______ 21.
Liquid dish detergent
______ 9.
Pizza
______ 22.
Calcium
______ 10.
Aluminum
______ 23.
Steam
______ 11.
Chocolate syrup
______ 24.
Raisin Bran © cereal
______ 12.
Hot chocolate with marshmallows
______ 25.
Italian salad dressing
______ 13.
Salt (NaCl)
______ 26.
Oxygen (O2)
8
Water, Acids, and Bases
Name: ____________________________________
Section 2.2
Date: _____________________ Period: _______
Water is one of the most important molecules in the body. Cells are made mostly of water and water is required
for almost every metabolic reaction in the body. The force of attraction between water molecules is so strong
that the oxygen atom of one molecule can actually remove the hydrogen from other water molecules. This
reaction is known as dissociation, and it takes place in our cells.
Water (H2O) dissociates into H+ and OH- ions. A charged atom or molecule is called an ion. The OH- ion is
called the hydroxide ion, while the H+ ion is called the hydrogen ion. Free H+ ions can react with another
water molecule to form the H3O+ or hydronium ion. The human body requires a neutral pH for many reasons.
One reason cells like a neutral pH is for proteins. Basic or acidic solutions denature proteins (change their
shape) so they no longer work.
1. What is dissociation? _____________________________________________________________________
_______________________________________________________________________________________
2. What is the chemical formula for water? _____________________________________________________
3. What is an ion? _________________________________________________________________________
4. Name the 2 ions form when water dissociates. _________________________________________________
5. What is the hydroxide ion?
_________________________________
6. What is a hydrogen ion?
_________________________________
9
Acidity or alkalinity is a measure of the relative amount of H+ and OH- ions dissolved in a solution. Neutral
solutions have an equal number of H+ and OH- ions. Acids have more H+ ions than OH- ions.
Acids taste sour and can be corrosive. Digestive fluids in the body are acidic and must be neutralized by
buffers. Bases contain more OH- ions than H+ ions. Bases taste bitter and feel slippery.
When an acid is combined with a base, neutralization occurs. The result of neutralization is a salt and water.
Neutralization helps return our body pH to neutral. The process of our bodies maintaining neutral pH so that
proteins can work properly without being denatured (unfolded) is known as homeostasis.
7. Acids have more _________________ ions than _________________ ions.
8. Bases contain more _________________ ions than _________________ ions.
Neutral solutions have an
number of H+ and OH- ions.
10
ACIDS, BASES, and pH
1. What makes pure water neutral? ____________________________________________________________
2. What does the pH scale measure? ___________________________________________________________
3. On the pH scale, indicate which direction is increasingly acidic and which is increasingly basic.
4. Identify two solutions that have more H+ ions than OH– ions.
____________________________________
5. Identify two solutions that have more OH– ions than H+ ions.
____________________________________
6.
Why are buffers important to living things?
______________________________________________________________________________________________
11
Properties of Water
Name: ______________________________
Section 2.2
Date: _________________ Period: ______
POLARITY AND HYDROGEN BONDING
1. If there are 600 water molecules in a glass. What is the total number of hydrogen atoms in the glass? What
is the total number of oxygen atoms in the glass? What is the total number of atoms in the glass?
2. Include the partial charges of each atom in the water molecule to the right.
3. Why is water considered to be a polar molecule?
4. Explain why the oxygen atom in water has a negative charge.
5. Explain why the two pictures below are incorrect:
6. What is the name of the bond formed between water molecules?
7. A student in biology class accidentally spills some vegetable oil on her favorite shirt. She tries to wash the
oil off of her shirt with water but she is unsuccessful. Explain why it would be impossible to remove an oil
stain with just water. Please talk about polarity in your answer.
_______________________________________________________________________________________
_______________________________________________________________________________________
The diagram shows a salt crystal (NaCl) being dissolved in water.
8. In this mixture identify the solute and solvent.
9. Why are the water molecules attracted to Cl- ions and the Na+ ions in the salt?
12
HEAT CAPACITY
10. As a substance is heated its molecules vibrate slower / faster.
11. Since water has a very high heat capacity the ocean temperature is very stable / unstable.
12. During a hot summer day the temperature of the water heats up much faster / slower than the temperature
of the air.
13. Most animals in the ocean are cold blooded which means that their body temperature is equal to the
temperature of the water. What would happen to the animals living in the ocean is that ocean temperature
was to rapidly change?
_______________________________________________________________________________________
_______________________________________________________________________________________
________________
STATES OF MATTER
14. Does cold water (not frozen) sink or float in warmer water?
Why?
15. Which state of water forms the most hydrogen
bonds?
16. Which state of water forms the least hydrogen
bonds?
17. What is the temperature range where water will
remain a liquid?
18. At what temperature must you cool water to allow
for a maximum of hydrogen bonding to take place?
19. Why do cracks in pavement widen over time to become pot holes during the winter?
13
COHESION AND ADHESION
20. Explain the difference between adhesion and cohesion?
21. The object was gently placed on the surface of a body of water. Draw in the hydrogen bonds that allow this
object that is denser to stay afloat.
22. How does waters polar nature account for
its high surface tension?
23. Why does it hurt more to do a belly flop into a pool of water than dive in pencil style?
______________________________
24. How do cohesion and adhesion explain capillary action?
If you lay a penny on a flat surface and add several drops of water on the face of the penny, the water will
form a dome that never spills off of the side of the penny.
25. Explain how adhesion and cohesion prevent the water from
spilling over the edge of the penny?
14
SOLUTIONS AND SUSPENSIONS
26. Why is water called the universal solvent? What does polarity have to do with this?
27. How does water dissolve a substance like NaCl?
28. What do the terms hydrophilic and hydrophobic mean?
ACIDS, BASES, AND PH
Matching: match the term with the following descriptions.
A. Polarity
B. Acidic
C. Basic
_______ 1.
Unequal sharing of electrons
_______ 2.
Lemon juice, pH 1.5
_______ 3.
Lower concentration of H+ ions than pure water
_______ 4.
Ammonia, pH 11.5
_______ 5.
A slight negative charge at one end of a molecule, a slight positive charge on the other end
_______ 6.
pH values that are below 7
_______ 7.
Alkaline solutions
15
2.4 Chemical Reactions and Enzymes
Name
Biology
Date
Period:
Objectives:
 Explain how chemical reactions affect chemical bonds.
 Describe how energy changes affect how easily a chemical reaction will occur.
 Explain why enzymes are important to living things.
Background Information:
Chemical Reactions - Everything that happens in an organism is based on chemical reactions. A chemical
reaction is a process that changes one set of chemicals into another set of chemicals.
 The elements or compounds that enter into the reaction are the reactants.
 The elements or compounds produced by the reaction are the products.
 Chemical reactions involve changes in the chemical bonds that join atoms in compounds.
Energy in Reactions - Some chemical reactions release energy; others absorb energy.
 Chemical reactions that release energy often occur on their own.
 Chemical reactions that absorb energy require a source of energy. The energy needed to get a reaction
started is called the activation energy.
Enzymes - An enzyme is a protein that acts as biological catalyst. A catalyst is a substance that speeds up the
rate of a chemical reaction. Catalysts work by lowering a reaction’s activation energy.
 In an enzyme-catalyzed reaction, the reactants are known as substrates. Substrates bind to a part of an
enzyme called the active site and remain bound to the enzyme until the reaction is complete, when the
products are released.
 Temperature, pH, and regulatory molecules can affect the activity of enzymes.
Chemical Reactions
1. What is a chemical reaction?
2. Complete the table about chemicals in a chemical reaction.
Chemicals in a Chemical Reaction
Term
Definition
Reactants
Products

16
Energy in Reactions
3. The graphs below show the amount of energy present during two chemical reactions. One of the reactions
is an energy-absorbing reaction, the other is an energy-releasing reaction.
LABEL the type of reaction for each, label the energy level for the reactants and products, and then
draw an arrow on each to show the energy of activation.
Type of reaction:
Type of reaction:
4. What is released or absorbed whenever chemical bonds are formed or broken?
5. What is the energy of activation?
6. Of the two reactions shown, which one is more likely to start spontaneously and why?
Enzymes
7. What is a catalyst?
8. Catalysts increase / decrease the rate of the reaction without being used up. (circle one)
9. What is a substrate?
10. How does the addition of a catalyst affect the energy of activation of a chemical reaction?
11. What type of catalysts affect biochemical reactions?
17
Use the diagram to answer the following questions. Label the enzyme, the active site, and the products in the
diagram.
12. Write what is happening at each numbered part of the diagram.
(1)
(2)
(3)
For the following questions, refer to the Visual Analogy comparing the action of enzymes to a lock and key.
13. How is a substrate and its enzyme like a lock and its key?
14. What is being unlocked in this analogy?
Some cells in your body can produce hydrogen peroxide (H2O2) to help fight infections. Hydrogen peroxide is
one of many chemicals that can help cells at low levels and harm them at high levels. The level of hydrogen
peroxide in a cell must be controlled. Hydrogen peroxide (H2O2) can break down into water (H2O) and oxygen
gas (O2). An enzyme called CATALASE helps speed up this reaction.
15. Identify the reactants, the products and the enzyme in the reaction by writing R, P or E over the substances
in the reaction.
2H2O2 + catalase  2H2O + O2 + catalase
Catalase is the enzyme, a biological (organic) catalyst. Hydrogen peroxide is the substrate for catalase.
18
16. Identify three factors that affect/influence enzyme activity:
1.
2.
3.
17. What happens to an enzyme (protein) that has lost its active conformation?
18. Hydrogen peroxide can undergo the chemical reaction WITHOUT the use of catalase. All it needs is a
little bit of energy to proceed to product. This process will just occur at a slower rate than with the catalase
present. Explain why companies that make hydrogen peroxide need to store the solution in the dark bottle.
19. Complete the concept map. Some terms have been placed in the concept map for you.
activation energy
catalysts
chemical reaction
enzymes
products
reactants
substrate
which work by
lowering
needed to start a
Chemical
reaction
such as the biological
ones called
can be sped up by
which begins with
elements or
compounds called
Enzymes
which bind to a
which combine to form
Products
19
Chapter 2 Review
Biology
Name:
Date:
Period:
Please review the following sections for the test:
 Section 2.1 – Chemistry
 Section 2.2 – Water
 Section 2.4 – Reactions and Enzymes
Discuss the following questions with your partner and write responses on this paper or another sheet of paper.
1. Compare and contrast:
a. protons, neutrons and electrons
b. neutral atoms vs. ions
c. ionic vs. covalent bonds
2. Determine the number of atoms in the following compounds:
a. NaOH
b. H2SO4
c. 4 Co(ClO4)2
d. 5 Al2(SO2)3
3. What is the formula for water?
a. Why is water polar?
b. How do hydrogen bonds form?
c. Draw 3 molecules of water with the partial charges and hydrogen bonds.
4. Compare and contrast:
a. Adhesion and cohesion
b. Capillary action and surface tension
5. Compare and contrast:
a. Element vs. Compound
b. Solution vs. Suspension
c. What are the parts of a solution
6. Compare and contrast:
a. Hydrophilic vs. Hydrophobic
b. Why is water a Universal Solvent?
7. Compare and contrast:
a. Acids and Bases – be specific in terms of H+ and OH- concentrations
 Water – why is it neutral?
b. How does pH change in an acid or a base
c. What is buffer?
8. Compare and contrast:
a. Reactants vs. Products
b. Endothermic vs. Exothermic reactions
9. Describe how enzymes work.
20
Inorganic Vocabulary Review
Sections 2.1 and 2.2
Section 2.1: The Nature of Matter
_______ 1. Anion
a) refers to the number of protons
_______ 2.
Atomic Mass
b) sum of protons and neutrons
_______ 3.
Atomic number
c) positive subatomic particle
_______ 4.
Cation
d) negative subatomic particle
_______ 5.
Covalent bond
e) subatomic particle with a neutral charge
_______ 6.
Electron
f) electrons are transferred from one atom to another.
_______ 7.
Ion
g) refers to outer energy electrons
_______ 8.
Ionic bond
h) when an atom gains or loses electrons
_______ 9.
Isomer
i) electrons are shared between atoms
_______ 10. Mass number
j) the same molecular formula, different arrangement of atoms
_______ 11. Neutron
k) weighted average of the isotopes of an element
_______ 12. Proton
l) gains electrons to form a negative charge
_______ 13. Valence
m) loses electrons to form a positive charge
Section 2.2: Properties of Water
_______ 1. Acid
a) mixture in which all the components are evenly distributed
_______ 2.
Adhesion
b) compound that produces hydroxide ions (OH-) in solution
_______ 3.
Base
c) mixture of water and non-dissolved material
_______ 4.
Buffer
d) substance that is dissolved in a solution
_______ 5.
Cohesion
e) compound that forms hydrogen ions (H+) in solution
_______ 6.
Hydrogen bonds
f) substance that does the dissolving in a solution
_______ 7.
Hydrophilic
g) compounds that prevents sharp, sudden changes in pH
_______ 8.
Hydrophobic
h) a molecule with an uneven distribution of electrons
_______ 9.
Polar Molecule
i) attraction between molecules of the same substance
_______ 10. Solute
j) force of attraction between different kinds of molecules
_______ 11. Solution
k) weak attraction between a hydrogen atom and another atom with a
_______ 12. Solvent
_______ 13. Suspension
partial negative charge
l) substance that is attracted to water; dissolves well in water
m) substance that is repelled by water; doesn’t dissolve in water
21
PROPERTIES OF WATER
ACROSS
2 A solution that produces more OH- ions then H+ ions.
6 An intermolecular force (bond) that forms between the negative end of one water molecule and the
positive end of another water molecule.
7 A solution that produces more H+ ions then OH- ions.
8 Water takes a long time to heat up and cool down because it has high ___________________.
9 A property of water where hydrogen bonds form between two molecules of the same substance.
10 A substance that resists changes in pH.
13 A term that describes a nonpolar substance that cannot be mixed with water.
14 Water molecules form hydrogen bonds to a different substance besides water is an example of ________.
15 A name for the substance that is being dissolved in a solution.
16 The substance does the dissolving in a solution.
DOWN
1
3
4
5
8
11
12
The state of water that has the most hydrogen bonds formed.
A measure of how difficult it is to break the surface of a liquid because of hydrogen bonds.
A subatomic particle that has a negative charge.
A term that describes a polar substance that can be mixed with water.
Maintaining internal stable internal body conditions.
A type of chemical bond where electrons are shared.
Any molecule that has a positive end or a negative because of an uneven distribution of electrons.
22
Use the clues and words to help you write the vocabulary terms from the chapter in the blanks. You may use a word once
or not at all.
enzyme
protons
valence
ion
neutrons
hydrophilic
substrate
electrons
cohesion
molecule
covalent
adhesion
nucleus
ionic
hydrophobic
1. Smallest particle of a covalent compound
2. A protein that can catalyze a chemical reaction
3. Water molecules stick to another substance
4. An atom that has gained or lost an electron
5. The center of an atom
6. Found in the nucleus
7. Bond formed from the transfer of electrons
8. Substance that repels water
9. Electrons responsible for bonding
10. Look at the pH scale to the right. Which of the following substances is the strongest acid?
A. tomato juice
B. milk
C. bleach
D. lemon juice
11. Look at the pH scale to the right. Which of the following substances is the
weakest base?
A. ammonia
B. milk
C. bleach
D. human blood
12. Look at the pH scale to the right. Which of the substances contains an equal
concentration of OH- and H+ ions?
13. Describe how an enzyme works (use the following terms: substrate, enzyme,
active site, products).
14. What effect does a catalyst have on the activation energy?
23
15. Describe the two main types of chemical bonds that are found in compounds.
________________________________________________________________________________________
________________________________________________________________________________________
16. If atoms lose one electron, they become charged particles or __________________ and will have a
____________________ charge. If they lose 3 electrons, the charge will be ___________.
17. If atoms gain electron(s), they will have a ____________________ charge. If they gain 3 electrons, the
charge will be _________.
18. Complete the table:
Compound
Number of Each Atom
Total Number of
Atoms
Number of
Molecules
C6H12O6
3 C6H12O6
CH3OH
Some cells in your body can produce hydrogen peroxide (H2O2) to help fight infections. Hydrogen peroxide is
one of many chemicals that can help cells at low levels and harm them at high levels. The level of hydrogen
peroxide (H2O2) in a cell must be controlled. Hydrogen peroxide can break down into water (H2O) and oxygen
gas (O2). An enzyme called CATALASE helps speed up this reaction.
19. Identify the reactants, the products and the enzyme in the reaction by writing R, P or E over the
substances in the reaction. Hydrogen peroxide is the substrate for catalase.
2H2O2 + catalase  2H2O + O2 + catalase
20. The diagram below shows how an enzyme like catalase works to break down a molecule like hydrogen
peroxide into smaller molecules. In the diagram below, label the following:
Catalase, H2O2, H2O, and O2
24
Venn Diagram - A Venn diagram is made up of overlapping circles. It is a useful tool for comparing two or even
three topics. In each circle, write one of the topics that you want to compare. In the space where the circles overlap,
write the features that the topics share. In the space where the circles do not overlap, write the features that are
unique to each topic.
25